1. Field of the Invention
The present invention relates generally to the treatment of bio-oil. More specifically, the invention concerns processes and systems for producing renewable fuels or fuel additives from bio-oil.
2. Description of the Related Art
With the rising costs and environmental concerns associated with fossil fuels, renewable energy sources have become increasingly important. The development of renewable fuel sources provides a means for reducing the dependence on fossil fuels. Accordingly, many different areas of renewable fuel research are currently being explored and developed.
With its low cost and wide availability, biomass has increasingly been emphasized as an ideal feedstock in renewable fuel research. Consequently, many different conversion processes have been developed that use biomass as a feedstock to produce useful biofuels and/or specialty chemicals. Existing biomass conversion processes include, for example, combustion, gasification, slow pyrolysis, fast pyrolysis, liquefaction, and enzymatic conversion. One of the useful products that may be derived from the aforementioned biomass conversion processes is a liquid product commonly referred to as “bio-oil.” Bio-oil may be processed into transportation fuels, hydrocarbon chemicals, and/or specialty chemicals.
Despite recent advancements in biomass conversion processes, many of the existing biomass conversion processes produce low-quality bio-oils containing high amounts of oxygen. These bio-oils require extensive secondary upgrading in order to be utilized as transportation fuels and/or as fuel additives due to the high amounts of oxygen present in the bio-oil. Furthermore, these transportation fuels and/or fuel additives derived from bio-oil vary in quality depending on the original oxygen content of the bio-oil.
Bio-oils can be subjected to various upgrading processes in order to process the bio-oil into renewable fuels and/or fuel additives. However, prior upgrading processes have been relatively inefficient and produce renewable fuels and/or fuel additives that have limited use in today's market. Furthermore, only limited amounts of these bio-oil derived transportation fuels and/or fuel additives may be combinable with petroleum-derived gasoline or diesel.
Accordingly, there is a need for an improved process and system for upgrading bio-oil into renewable fuels and/or fuel additives.